drivers/md/dm-init.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2
   3 /*
   4  * Copyright (C) 2017 The Chromium OS Authors <chromium-os-dev@chromium.org>
   5  *
   6  * This file is released under the GPLv2.
   7  */
   8
   9 #include <linux/ctype.h>
  10 #include <linux/delay.h>
  11 #include <linux/device.h>
  12 #include <linux/device-mapper.h>
  13 #include <linux/init.h>
  14 #include <linux/list.h>
  15 #include <linux/moduleparam.h>
  16
  17 #define DM_MSG_PREFIX "init"
  18 #define DM_MAX_DEVICES 256
  19 #define DM_MAX_TARGETS 256
  20 #define DM_MAX_STR_SIZE 4096
  21 #define DM_MAX_WAITFOR 256
  22
  23 static char *create;
  24
  25 static char *waitfor[DM_MAX_WAITFOR];
  26
  27 /*
  28  * Format: dm-mod.create=<name>,<uuid>,<minor>,<flags>,<table>[,<table>+][;<name>,<uuid>,<minor>,<flags>,<table>[,<table>+]+]
  29  * Table format: <start_sector> <num_sectors> <target_type> <target_args>
  30  * Block devices to wait for to become available before setting up tables:
  31  * dm-mod.waitfor=<device1>[,..,<deviceN>]
  32  *
  33  * See Documentation/admin-guide/device-mapper/dm-init.rst for dm-mod.create="..." format
  34  * details.
  35  */
  36
  37 struct dm_device {
  38         struct dm_ioctl dmi;
  39         struct dm_target_spec *table[DM_MAX_TARGETS];
  40         char *target_args_array[DM_MAX_TARGETS];
  41         struct list_head list;
  42 };
  43
  44 static const char * const dm_allowed_targets[] __initconst = {
  45         "crypt",
  46         "delay",
  47         "linear",
  48         "snapshot-origin",
  49         "striped",
  50         "verity",
  51 };
  52
  53 static int __init dm_verify_target_type(const char *target)
  54 {
  55         unsigned int i;
  56
  57         for (i = 0; i < ARRAY_SIZE(dm_allowed_targets); i++) {
  58                 if (!strcmp(dm_allowed_targets[i], target))
  59                         return 0;
  60         }
  61         return -EINVAL;
  62 }
  63
  64 static void __init dm_setup_cleanup(struct list_head *devices)
  65 {
  66         struct dm_device *dev, *tmp;
  67         unsigned int i;
  68
  69         list_for_each_entry_safe(dev, tmp, devices, list) {
  70                 list_del(&dev->list);
  71                 for (i = 0; i < dev->dmi.target_count; i++) {
  72                         kfree(dev->table[i]);
  73                         kfree(dev->target_args_array[i]);
  74                 }
  75                 kfree(dev);
  76         }
  77 }
  78
  79 /**
  80  * str_field_delimit - delimit a string based on a separator char.
  81  * @str: the pointer to the string to delimit.
  82  * @separator: char that delimits the field
  83  *
  84  * Find a @separator and replace it by '\0'.
  85  * Remove leading and trailing spaces.
  86  * Return the remainder string after the @separator.
  87  */
  88 static char __init *str_field_delimit(char **str, char separator)
  89 {
  90         char *s;
  91
  92         /* TODO: add support for escaped characters */
  93         *str = skip_spaces(*str);
  94         s = strchr(*str, separator);
  95         /* Delimit the field and remove trailing spaces */
  96         if (s)
  97                 *s = '\0';
  98         *str = strim(*str);
  99         return s ? ++s : NULL;
 100 }
 101
 102 /**
 103  * dm_parse_table_entry - parse a table entry
 104  * @dev: device to store the parsed information.
 105  * @str: the pointer to a string with the format:
 106  *      <start_sector> <num_sectors> <target_type> <target_args>[, ...]
 107  *
 108  * Return the remainder string after the table entry, i.e, after the comma which
 109  * delimits the entry or NULL if reached the end of the string.
 110  */
 111 static char __init *dm_parse_table_entry(struct dm_device *dev, char *str)
 112 {
 113         const unsigned int n = dev->dmi.target_count - 1;
 114         struct dm_target_spec *sp;
 115         unsigned int i;
 116         /* fields:  */
 117         char *field[4];
 118         char *next;
 119
 120         field[0] = str;
 121         /* Delimit first 3 fields that are separated by space */
 122         for (i = 0; i < ARRAY_SIZE(field) - 1; i++) {
 123                 field[i + 1] = str_field_delimit(&field[i], ' ');
 124                 if (!field[i + 1])
 125                         return ERR_PTR(-EINVAL);
 126         }
 127         /* Delimit last field that can be terminated by comma */
 128         next = str_field_delimit(&field[i], ',');
 129
 130         sp = kzalloc(sizeof(*sp), GFP_KERNEL);
 131         if (!sp)
 132                 return ERR_PTR(-ENOMEM);
 133         dev->table[n] = sp;
 134
 135         /* start_sector */
 136         if (kstrtoull(field[0], 0, &sp->sector_start))
 137                 return ERR_PTR(-EINVAL);
 138         /* num_sector */
 139         if (kstrtoull(field[1], 0, &sp->length))
 140                 return ERR_PTR(-EINVAL);
 141         /* target_type */
 142         strscpy(sp->target_type, field[2], sizeof(sp->target_type));
 143         if (dm_verify_target_type(sp->target_type)) {
 144                 DMERR("invalid type \"%s\"", sp->target_type);
 145                 return ERR_PTR(-EINVAL);
 146         }
 147         /* target_args */
 148         dev->target_args_array[n] = kstrndup(field[3], DM_MAX_STR_SIZE,
 149                                              GFP_KERNEL);
 150         if (!dev->target_args_array[n])
 151                 return ERR_PTR(-ENOMEM);
 152
 153         return next;
 154 }
 155
 156 /**
 157  * dm_parse_table - parse "dm-mod.create=" table field
 158  * @dev: device to store the parsed information.
 159  * @str: the pointer to a string with the format:
 160  *      <table>[,<table>+]
 161  */
 162 static int __init dm_parse_table(struct dm_device *dev, char *str)
 163 {
 164         char *table_entry = str;
 165
 166         while (table_entry) {
 167                 DMDEBUG("parsing table \"%s\"", str);
 168                 if (++dev->dmi.target_count > DM_MAX_TARGETS) {
 169                         DMERR("too many targets %u > %d",
 170                               dev->dmi.target_count, DM_MAX_TARGETS);
 171                         return -EINVAL;
 172                 }
 173                 table_entry = dm_parse_table_entry(dev, table_entry);
 174                 if (IS_ERR(table_entry)) {
 175                         DMERR("couldn't parse table");
 176                         return PTR_ERR(table_entry);
 177                 }
 178         }
 179
 180         return 0;
 181 }
 182
 183 /**
 184  * dm_parse_device_entry - parse a device entry
 185  * @dev: device to store the parsed information.
 186  * @str: the pointer to a string with the format:
 187  *      name,uuid,minor,flags,table[; ...]
 188  *
 189  * Return the remainder string after the table entry, i.e, after the semi-colon
 190  * which delimits the entry or NULL if reached the end of the string.
 191  */
 192 static char __init *dm_parse_device_entry(struct dm_device *dev, char *str)
 193 {
 194         /* There are 5 fields: name,uuid,minor,flags,table; */
 195         char *field[5];
 196         unsigned int i;
 197         char *next;
 198
 199         field[0] = str;
 200         /* Delimit first 4 fields that are separated by comma */
 201         for (i = 0; i < ARRAY_SIZE(field) - 1; i++) {
 202                 field[i+1] = str_field_delimit(&field[i], ',');
 203                 if (!field[i+1])
 204                         return ERR_PTR(-EINVAL);
 205         }
 206         /* Delimit last field that can be delimited by semi-colon */
 207         next = str_field_delimit(&field[i], ';');
 208
 209         /* name */
 210         strscpy(dev->dmi.name, field[0], sizeof(dev->dmi.name));
 211         /* uuid */
 212         strscpy(dev->dmi.uuid, field[1], sizeof(dev->dmi.uuid));
 213         /* minor */
 214         if (strlen(field[2])) {
 215                 if (kstrtoull(field[2], 0, &dev->dmi.dev) ||
 216                     dev->dmi.dev >= (1 << MINORBITS))
 217                         return ERR_PTR(-EINVAL);
 218                 dev->dmi.dev = huge_encode_dev((dev_t)dev->dmi.dev);
 219                 dev->dmi.flags |= DM_PERSISTENT_DEV_FLAG;
 220         }
 221         /* flags */
 222         if (!strcmp(field[3], "ro"))
 223                 dev->dmi.flags |= DM_READONLY_FLAG;
 224         else if (strcmp(field[3], "rw"))
 225                 return ERR_PTR(-EINVAL);
 226         /* table */
 227         if (dm_parse_table(dev, field[4]))
 228                 return ERR_PTR(-EINVAL);
 229
 230         return next;
 231 }
 232
 233 /**
 234  * dm_parse_devices - parse "dm-mod.create=" argument
 235  * @devices: list of struct dm_device to store the parsed information.
 236  * @str: the pointer to a string with the format:
 237  *      <device>[;<device>+]
 238  */
 239 static int __init dm_parse_devices(struct list_head *devices, char *str)
 240 {
 241         unsigned long ndev = 0;
 242         struct dm_device *dev;
 243         char *device = str;
 244
 245         DMDEBUG("parsing \"%s\"", str);
 246         while (device) {
 247                 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 248                 if (!dev)
 249                         return -ENOMEM;
 250                 list_add_tail(&dev->list, devices);
 251
 252                 if (++ndev > DM_MAX_DEVICES) {
 253                         DMERR("too many devices %lu > %d",
 254                               ndev, DM_MAX_DEVICES);
 255                         return -EINVAL;
 256                 }
 257
 258                 device = dm_parse_device_entry(dev, device);
 259                 if (IS_ERR(device)) {
 260                         DMERR("couldn't parse device");
 261                         return PTR_ERR(device);
 262                 }
 263         }
 264
 265         return 0;
 266 }
 267
 268 /**
 269  * dm_init_init - parse "dm-mod.create=" argument and configure drivers
 270  */
 271 static int __init dm_init_init(void)
 272 {
 273         struct dm_device *dev;
 274         LIST_HEAD(devices);
 275         char *str;
 276         int i, r;
 277
 278         if (!create)
 279                 return 0;
 280
 281         if (strlen(create) >= DM_MAX_STR_SIZE) {
 282                 DMERR("Argument is too big. Limit is %d", DM_MAX_STR_SIZE);
 283                 return -EINVAL;
 284         }
 285         str = kstrndup(create, DM_MAX_STR_SIZE, GFP_KERNEL);
 286         if (!str)
 287                 return -ENOMEM;
 288
 289         r = dm_parse_devices(&devices, str);
 290         if (r)
 291                 goto out;
 292
 293         DMINFO("waiting for all devices to be available before creating mapped devices");
 294         wait_for_device_probe();
 295
 296         for (i = 0; i < ARRAY_SIZE(waitfor); i++) {
 297                 if (waitfor[i]) {
 298                         dev_t dev;
 299
 300                         DMINFO("waiting for device %s ...", waitfor[i]);
 301                         while (early_lookup_bdev(waitfor[i], &dev))
 302                                 fsleep(5000);
 303                 }
 304         }
 305
 306         if (waitfor[0])
 307                 DMINFO("all devices available");
 308
 309         list_for_each_entry(dev, &devices, list) {
 310                 if (dm_early_create(&dev->dmi, dev->table,
 311                                     dev->target_args_array))
 312                         break;
 313         }
 314 out:
 315         kfree(str);
 316         dm_setup_cleanup(&devices);
 317         return r;
 318 }
 319
 320 late_initcall(dm_init_init);
 321
 322 module_param(create, charp, 0);
 323 MODULE_PARM_DESC(create, "Create a mapped device in early boot");
 324
 325 module_param_array(waitfor, charp, NULL, 0);
 326 MODULE_PARM_DESC(waitfor, "Devices to wait for before setting up tables");